中文摘要：

森林是陆地生态系统的主体，在全球碳循环中起着十分重要的作用。本文利用20世纪70年代以来的六次森林清查资料．结合森林生物量实测数据。采用分树种、分龄组的生物量一蓄积拟合关系．估算了中国20世纪70年代以来森林植被碳储量的动态变化。结果表明：我国六次森林资源清查中森林的植被总碳储量分别为3．8488PgC、3．6960PGC、3．759PGC、4．1138PgC、4．6563PgC和5．5064PGC，虽然存在一定的波动现象，但总体增长趋势明显，尤其是80年代以来，植被碳储量净增加1．8104PgC．平均每年以0．0823PgC的速率增加．这表明80年代以来我国森林植被一直起着明显的CO2汇的作用。从碳密度的变化看，70年代以来我国森林植被平均碳密度增长了3．001Mgha^-1．其中幼龄林与中龄林碳密度分别增长5．2871Mgha^-1和0．6022Mgha^-1．而成熟林碳密度却降低了0．7581Mgha^-1．可见中国森林植被的碳汇功能主要来自于人工林的贡献，而且随着幼龄林、中龄林碳储量和碳密度的增长．中国森林植被的碳汇功能将进一步增强。我国森林植被碳储量和碳密度空间差异显著。森林植被碳库主要集中于东北和西南地区．平均碳密度以西南、东北以及西北地区为大．中国森林植被碳储量和碳密度的这种空间分布规律与人类活动对森林的干扰强度密切相关。

英文摘要：

Forest is the first major form of terrestrial ecosystem and plays an important dominant role in global carbon cycle. In this study, we developed an age-based volume-to-biomass method to estimate the carbon storage of Chinese forests between 1973 and 2003 by using inventory data of six periods and forest biomass data obtained from direct field measurements. The results show that the total vegetation carbon storage of Chinese forests in the six periods （1973- 1976, 1977-1981, 1984-1988, 1989-1993, 1994-1998 and 1999-2003） is 3.8488 PgC, 3.6960 PgC, 3.759 PgC, 4.1138 PgC, 4.6563 PgC and 5.5064 PgC, respectively. Although the results of different periods is fluctuates their trends are an increase with the time. Especially, since 1980s the total vegetation carbon storage of Chinese forests has increased 1.8104PGC and accumulated about 0.0823PGC per year. It means that Chinese forests play a role as a significant sink of atmospheric carbon dioxide in that period. On the other hand, the mean carbon density of Chinese forests has increased 3.001Mgha^-1 since 1970s, and that of young and mlddle-aged forests has increased 5.2871 and 0.6022Mgha^-1, respectively, but that of mature forests has decreased by 0.7581Mgha^-1. This phenomenon suggests that the carbon fixation ability of Chinese forests primarily derives from forest plantation and it would be enhanced with carbon storage and carbon density increasing of young and middle-aged forests. The carbon stocks and densities of Chinese forests vary greatly in space. The larger carbon storage is primarily found in north eastern and south western regions, and higher C density mostly occurs in north eastern, south western and north western regions. These spatial distribution characteristics of carbon storage and mean C density in Chinese forests are prominently determined by human activities.